WO1997048149A1

WO1997048149A1 - Pin bushing

Info

Publication number: WO1997048149A1
Application number: PCT/EP1997/003013
Authority: WO
Inventors: Steffen Müller; Friedrich PREBÖCK; Rudolf Nottrott; Rudolf Michler
Original assignee: Framatome Connectors International
Priority date: 1996-06-14
Filing date: 1997-06-10
Publication date: 1997-12-18
Also published as: EP0904612A1; BR9709712A; ATE210900T1; EP0904612B1; CA2257604A1

Abstract

The present invention relates to a pin bushing (1) with a receiving part (2) for a pin (4) and a side connection part (3). The receiving part (2) forms a bushing (5) with a base (6), two side walls (7a, 7b) and a roof zone (8), the roof zone (8) comprising at least two tongues (9) alternatively radiating from different side walls (7a, 7b) and extending transversely of the plug-in direction, said tongues being bent over inwards into the bushing (5) in the top zone of the opposite side walls (7a, 7b).

Description

Pin bushing

This invention relates to a pin bushing in accordance with the preamble of claim 1.

Pin bushings of this kind are used, individually or combined in a plurality in casings, with matching pins in order to produce plugged-in connections.

The quality of a plugged-in connection is governed by secure hold of the pin in the bushing, and this is dependent on mechanical properties and good electrical contact or low transition resistance, which in turn depends on the firm fit of the pin in the bushing.

The object of this invention is to provide an improved pin bushing of small dimensions, suitable particularly for heavy current, to guarantee a very firm fit of the pin in the bushing, while ensuring low electrical transition resistance by preventing fretting corrosion.

This problem is solved by the feature of claim 1.

Features of preferred embodiments of the invention are disclosed in the subclaims. The resilient construction of the tongues which make contact in the roof zone of the pin bushing ensures both a firm fit of the pin in the bushing and also good electrical contact. The latter is due to the fact that even if a pin is tilted when introduced the tongues can bear against the pin surface in the optimal manner.

The provision of a longitudinal rib in the bottom zone of the bushing also ensures that in the event of the pin being tilted there is adequate contact area between the pin and the bushing.

The invention will be explained hereinafter with refe¬ rence to the description of one exemplified embodiment and the drawing wherein:

Fig. 1 is a side view and a plan view of the pin bushing according to the invention and

Fig. 2a is a cross-section through the bushing zone of a first embodiment of the pin bushing according to the invention.

Fig. 2b is a cross-section through the bushing zone of a second embodiment of the pin bushing according to the invention.

Fig. 2c is a cross-section through the bushing zone of a third embodiment of the pin bushing according to the invention.

Fig. 3 shows a metal stamping from which the bushing is made. Figs. 4a and 4b show the web surmounting the roof and

Fig. 5 shows windows provided in the front side walls of the bushing.

Fig. la shows the pin bushing 1 from the side. The re¬ ceiving part 2 is on the right. The cable connection part 3 is on the left. The tip of a pin part 4 is shown dia- grammatically on the right next to the pin bushing 1. The pin part 4 is plugged into the receiving part 2, which has the shape of a substantially rectangular bushing 5. Locking springs 12 are formed in the side walls of the bushing part and lock the pin bushing, in a housing if required.

The cable connection part 3 is in this case shown in the form of a crimp connection part, although this has no limiting force. Any other fixing technique is possible here and, accordingly, any suitable construction of the cable connection part 3.

Fig. lb is a plan view of the pin bushing according to the invention and the tip of a contact pin 4. It will be seen that the roof zone of the bushing 5 consists of, tongues 9, the construction of which will be apparent in detail from the description of Fig. 2. These tongues 9 are extensions of the side walls and are folded over through about 90° so that the top part thereof extends substantially parallel to the bottom zone of the bushing. In the example shown here, four tongues are distributed over the roof zone of the bushing and each extend trans¬ versely of the plug-in direction and are each formed alternately on opposite side walls. Just before the op¬ posite side wall, the tongues 9 are bent away obliquely inwards and have a length so selected that the tips of the tongues 9 terminate just before the side wall from which the tongue projects. Fig. lb again shows the locking springs 12 bent out of the side walls.

Fig. 2a is a cross-section through the bushing zone 5 of a first embodiment of the pin bushing 1 according to the invention, showing the shape of the tongues 9 more clear¬ ly. It will be seen that the tongue 9 in the foreground starts from the left side wall 7a and substantially its first half forms the outer contour of the roof zone 8 of the pin bushing. Just before reaching the opposite side wall 7b, the tongue is bent inwards, care being taken in respect of the angle of curvature to ensure that the front zone of the tongue has maximum elasticity when bent through the curvature zone, and to ensure that the front tongue zone rests as flatly as possible on the outer surface of the pin when the pin 4 is inserted. The non-hatched tongue 9, which extends from the opposite side wall 7b, is arranged in mirror-symmetry in relation to the hatched tongue with respect to the central ver¬ tical of the section shown in Fig. 2a. The tips 11 in the unstressed position shown here are at a certain distance from the side walls 7a, 7b, but this distance decreases as soon as they are pressed upwards as a result of the introduction of the contact pin 4. Preferably, the length of the tongues is so selected that even when the pin 4 is inserted the contact tips remain in contact with the pin surface . Fig. 2b shows a second embodiment of the inventive pin bushing which is considerably flatter in the bushing zone as compared to the embodiment shown in Fig. 2a. This comes from the fact that in the roof zone the tongues are only slightly bent inwards instead of being fold back¬ wards. In the embodiment shown in Fig. 2b the tongues, seen from their ends, are unbent up to their base in the upper area of the side walls. Only the bending fold at the upper side edge is curved here.

Alternatively to the embodiment shown in Fig. 2a here also the rib 10 in the bottom zone is designed diffe¬ rently. Here the rib has a semicircular cross-section which comes from the bottom part being punched out in the area of the rib 10 along the longitudinal edges thereof and the rib being subsequently bent upwards with the side edges thereof.

Fig. 2c also shows a flat embodiment of the bushing zone, in which, however, the tongues are slightly bent over the entire length thereof, and in which the rib is punched out of the bottom zone of the bushing along the longitu¬ dinal edges thereof.

By means of the punched-out ribs 10 also in the bottom zone of the pin bushing it is ensured that in the case of a tilted insertion of a plug lance an optimal electrical contact is guaranteed, since the surface of the rib can adapt itself to the tilting to a certain extent.

Figs. 4a and 4b show an alternative embodiment wherein a web 13 is formed at the top end of the right-hand side wall 7b and surmounts the roof zone 8 of the bushing 5 and is bent on the left-hand side to bear against the side wall 7a. A kind of cage is formed as a result which effectively prevents unintentional opening of the bushing.

A rib 10 (Fig. 2) is provided in the bottom zone 6 of the bushing 5 and extends in the plug-in direction. This rib creates specific contact relationships with the pin 4, since the flanks of the rib slope away on both sides to ensure secure support of the pin surface .

Instead of the rib 10 shown here with a flat platformlike surface, it is also possible to provide two parallel ribs of convexly curved cross-section if required. Since the tips 11 of the tongues 9 each exert pressure on the side edges of the top surface of the contact pins, effective pressure on the opposite rib 10 is guaranteed.

This effectively compensates for any tilting on intro¬ duction of the pin 4.

The electrical transition resistance is thus kept low and the mechanical static friction between the pin and the bushing is increased.

Fig. 3 shows a metal semiproduct consisting of a metal stamping from which the contact bushing according to the invention is made. The broken lines correspond to the folding edges about which the metal is bent through 90° in each case to form the contact bushing. Reinforcing ribs 16 will be seen on the tongues 9, such ribs being disposed on the longitudinal centre-line of the tongues 9 in the longitudinal direction to reinforce the tongues in this zone.

The edges of the tongues 9 are rounded as will be apparent from reference 15 in Fig. 3. Since these edges may possibly come into contact with the pin, as will be apparent from Fig. 2, it is important that there should be no catching or damage to the coating of the pin at this place, e.g. due to a sharp edge or a burr.

Figs. 4a and 4b show windows 14 in the side walls, in addition to the web 13 already mentioned.

Fig. 5 shows the cage 17 disposed around the bushing zone in order to protect it against opening up and guide lips 19a, 19b which are provided in the receiving zone of the bushing and which correctly position the pin on introduction into the bushing.

The above description of one exemplified embodiment has no limiting force. On the contrary, the invention covers all possible variants within the scope of the claims.

Claims

C L A I M S

1. A pin bushing (1) with a receiving part (2) for a pin (4) and a side connection part (3) , characterised in that the receiving part (2) forms a bushing (5) with a base (6) , two side walls (7a, 7b) and a roof zone (8) , the latter comprising at least two tongues (9) alter¬ nately radiating from different side walls (7a; 7b) and extending transversely of the plug-in direction, said tongues being bent over inwards into the bushing (5) in the top zone of the opposite side walls (7a, 7b) .

2. A pin bushing according to claim 1, characterised in that the tongues (9) at the upper end of the side walls (7a, 7b) are bent and, from there up to their ends, are straight .

3. A pin bushing according to claim 1, characterised in that the tongues (9) are bent over their entire lengths towards the interior of the bushing.

4. A pin bushing according to claim 1, characterised in that the tongues extend obliquely downwards towards the side walls (7b, 7a) from which they respectively extend.

5. A pin bushing according to claim 1, characterised in that at least one inwardly projecting rib (10) oriented longitudinally of the plug-in direction is disposed in the base (6) of the bushing.

6. A pin bushing according to claim 5, characterised in that the rib (10) is punched out at the longitudinal edges thereof.

7. A pin bushing according to claim 5, characterised in that the rib (10) is punched out at the longitudinal edges thereof and is semicircularly bent in cross- section.

8. A pin bushing according to one of the claims 1 to 4 , characterised in that a web (13) engaging around the opposite edge of the bushing starts from that side wall which is opposite the side wall (7a, 7b) from which a tongue (9) starts.

9. A pin bushing according to any of the preceding claims, characterised in that the cross-section of the bushing zone (5) of the receiving part is substantially rectangular.

10. A pin bushing according to any one of the preceding claims, characterised in that when the pin part (4) is plugged in the bent or bent-over part of the tongue extends substantially parallel to the pin surface and is pressed elastically against the latter.

11. A pin bushing according to claim 10, characterised in that the distance between the ends (11) of tongues (9) of opposite orientation is smaller, transversely of the plug-in direction when the pin is plugged-in, than the pin width (4) .

12. A pin bushing according to any one of the preceding claims, characterised in that the side connection part (3) is a crimp connection part.

13. A pin bushing according to any one of the preceding claims, characterised in that the side walls of the bushing (5) comprise locking springs (12) for locking in a casing.

14. A pin bushing according to any one of the preceding claims, characterised in that the tongues (9) comprise, at least in the roof zone (8) , at least one reinforcing rib (16) extending parallel to their longitudinal dimen¬ sion.

15. A pin bushing according to any one of the preceding claims, characterised in that the front edges (15) of the tongues (9) are rounded.

16. A pin bushing according to any one of the preceding claims, characterised in that windows (14) are formed in the side walls in the front zone of the bushing.

17. A pin bushing according to any one of the preceding claims, characterised in that a cage (17) surrounds the contact zone and has, at the entry end of the bushing, at least one guide lip (19a, 19b) to guide the pin on its introduction into the bushing.